Revert of Don't include scroll offset in offsetFromLayoutObject for scrolling contents layers.

Revert of Don't include scroll offset in offsetFromLayoutObject for scrolling contents layers. (patchset #17 id:160002 of https://codereview.chromium.org/2019583002/ )

Reason for revert:
Speculative revert for very small likelihood of causing elevated crash rates as detailed in https://bugs.chromium.org/p/chromium/issues/detail?id=616399

Original issue's description:
> Don't include scroll offset in offsetFromLayoutObject for scrolling contents layers.
> 
> As a side-effect, this patch changes the system to no longer invalidate both the scrolling contents layer and m_graphicsLayer, since they now have different coordinate systems. (This has been a long-standing bug.)
> 
> BUG=529938, 416535
> 
> Committed: https://crrev.com/66797e1dd0c3366619ebcc6a5ce3f546055d9103
> Cr-Commit-Position: refs/heads/master@{#396951}

TBR=wangxianzhu@chromium.org,wkorman@chromium.org,chrishtr@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=529938, 416535

[scottmg, 2016-06-08 00:09:39]

The CQ bit was checked by scottmg@chromium.org

[scottmg, 2016-06-08 00:09:39]

Created Revert of Don't include scroll offset in offsetFromLayoutObject for
scrolling contents layers.

[commit-bot: I haz the power, 2016-06-08 00:10:18]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2046233002/1

[commit-bot: I haz the power, 2016-06-08 00:13:53]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-06-08 00:13:55]

Try jobs failed on following builders:
  android_arm64_dbg_recipe on tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/android_arm6...)
  android_clang_dbg_recipe on tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/android_clan...)
  linux_chromium_chromeos_ozone_rel_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  linux_chromium_clobber_rel_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  ios-device on tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios-device/builds...)
  ios-device-gn on tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios-device-gn/bui...)
  mac_chromium_compile_dbg_ng on tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_comp...)
  mac_chromium_gn_rel on tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_gn_r...)
  mac_chromium_rel_ng on tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)